The invention is intended for the opthalmology sector of the market, within the area of optical applications of a therapeutic and/or prophylactic nature.
The object of this invention is a transparent filtering vehicle component for the protection of healthy eyes, pseudophakic eyes (eyes that have undergone cataract surgery) and/or eyes with macular and retinal degeneration, from short wavelengths of light. It is produced by applying a filter comprising a yellow pigment to the transparent or translucent surface/s of vehicles to protect eyes from the short wavelengths of the visible spectrum (500 to 380 nm). As an example, this component could be applied to windshields, or windscreens, of cars, buses, trains, planes, and other vehicles.
Visual perception is the result of the response to visible radiation in the wavelength range 380-760 nm. In the environment, solar radiation is the main risk factor for vision. The sun emits UV rays and IR radiation, which are mainly absorbed by the atmosphere. When the solar radiation transmitted through the atmosphere reaches the Earth's surface, it consists of UV-B rays (230-300 nm), UV or UV-A rays (300-380 nm), visible light rays (380-760 nm) and IR rays (760-1400 nm). Healthy human eyes freely transmit IR rays and those of most of the visible spectrum to the retina, but the cornea and crystalline lens prevent the most reactive wavelengths of the visible spectrum (UV-B rays and the blue portion of the spectrum) from reaching the retina.
The human crystalline lens changes its transmission properties as it ages by intensifying its yellow color thus increasing its capacity to filter out UV and blue light rays. Hence, in persons older than 65 years, ultraviolet light (<400 nm) is not transmitted and the transmission of blue light (400-500 nm) is markedly reduced.
The retina is capable of protecting itself from short wavelengths of light in two ways: through its uneven distribution of photoreceptors, such that there are no photoreceptors sensitive to blue light in the macular depression; and through the actions of yellow pigments in this zone, which also exert a protective effect.
These natural protection systems the human eye has against the shorter wavelengths of light—the crystalline lens and structures of the retina—can be seriously affected by certain diseases and/or surgical procedures: cataracts, whose surgical treatment involves the removal of the crystalline lens; additionally, it is common to find a pathological aging ageing process that causes degradation of the retinal structures producing age-related macular degeneration (AMD).
Both cataracts and AMD can coexist in persons older than 65 years. In this population of elderly subjects, cataracts are the main cause of vision loss and AMD is the main cause of blindness. In addition, an increase in both these diseases can be expected due, among other factors, to increased life expectancy. This translates into a great interest in these diseases and their treatment options in the research field and optics industry.
Several epidemiological studies have evaluated the relationship between cataract surgery and AMD. Thus, Klein (Klein R, Klein B E, Wong T Y, Tomany S C, Cruickshanks K J. The association of cataract and cataract surgery with the long-term incidence of age-related maculopathy. Arch Opthalmol 120:1551-1558. 2002) and Freeman (Freeman E, Muñoz B, West S K, Tielsch J M, Schein O D. Is there an association between cataract surgery and age-related macular degeneration? Am J Opthalmol 135 (6): 849-856. 2003) claim there is a higher risk of developing symptoms of AMD in persons who have undergone cataract surgery.
However, in earlier investigations by Wang (Wang J J, Mitchell P, Cumming R G, Lim R. Cataract and age-related maculopathy: the Blue Mountains Eye Study. Ophthalmic Epidemiol 6: 317-326.1999) and McCarty (McCarty C A, Mukesh B N, Fu C L, Mitchell P, Wang J J, Taylor H R. Risks factors for age-related maculopathy: the Visual Impairment Project. Arch Opthalmol 119:1455-1462. 2001) this hypothesis was rejected, possibly because of the less developed technology used for their diagnostic measurements. Techniques such as optical coherence tomography that allow the accurate, rapid, and non-invasive follow up of retinal neurodegeneration processes have only recently been introduced. These techniques are essential for monitoring the determining effect of the natural pigments that absorb harmful radiations.
Several techniques have also been developed to protect eyes subjected to cataract surgery from short wavelengths of light.
There are several types of filters containing a yellow pigment on the market, yet there is no optimal procedure and/or device to apply these filters to the human eye as a preventive and/or therapeutic measure to replace and/or improve the eye's natural protection.
Since the mid-1990s, eyes undergoing cataract extraction have been implanted with intraocular lenses containing a yellow pigment to act as a filter. This option requires surgical intervention with all its associated risks and difficulties. There is also a large population of subjects who have been implanted with a transparent lens to replace the natural lens during cataract surgery who are therefore devoid of the necessary protection. In these patients, the artificial crystalline lens, lacking a yellow pigment, needs to be complemented with a system to support the yellow pigment such as the vehicle component that is the object of the present invention.
Several patents related to the state of this technique have been developed (for healthy, pseudoaphakic and/or neurodegenerating eyes) although they differ considerably from the object of the present invention:                Solar visors for a vehicle windscreen (Korean patent document no. 9 205 420 B) comprised of polarized filters, among other components.        Windscreen photodetector (Japanese patent document no. 5 912 6935) to improve visibility in a vehicle.        Motorcar windscreen (Japanese patent document no. 5 804 9514) that prevents direct sunlight entering the eyes without narrowing the field of vision through the use of coloured sections.        Indicator for vehicles that prevents double images (Japanese patent document no. 5 193 397).        Vision system for the outside mirror of a vehicle (Japanese patent document no. 1 031 5763) that avoids glare due to vehicles in the rear.        Image emission system with a reduced emission angle (French patent document no. 2 811 089) that avoids reflections for use in aeroplane cockpits.        Phosphate glass containing copper for use in aeroplane cockpits (U.S. Pat. No. 6,252,702). This glass attenuates infrared radiation avoiding the risk of temporary blindness in the pilot without limiting visibility.        Optical media and procedure for improving or modifying colour vision and method for preparing them (U.S. Pat. No. 5,774,202) using a colour filter with a specific transmission range. For use on any type of surface including glass.        Visual discerning filter (Japanese patent document no. 6 108 7106) to avoid the change in luminosity that follows a change in tone and reduce the eye effort by providing the maximum absorption possible.        Ultraviolet filter and glass comprised of this filter (Japanese patent document no. 1 002 0347), whose transmittance of this type of radiation is variable and adjustable.        Electromagnetic filter (Japanese patent document no. 2000 349542 and 2000 349541) that protects against certain magnetic frequencies received, for example, through windows.        Absorption filter for color exposure systems (U.S. Pat. No. 5,121,030) that, through the application of dyes, improves visibility in conditions of high luminous intensity.        Colour highlighting filter and method of use to improve human vision (U.S. Pat. No. 6,158,865). Various embodiments of the invention comprises a filter that improves vision in all light environments including extreme ambient light and low illumination levels, and incorporates an adapting ring for the filter.        Special optical filters for certain activities and optical accessories that use these filters (U.S. Pat. No. 6,893,127) to improve the visualization of objects, for example in sports activities.        
These devices differ from various embodiments of the present invention mainly in their purpose and utility since none has been designed as a prevention/protection device for eyes against the harmful effects of short wavelengths of light. Moreover, most of these patents do not refer to the application of a filter to the transparent surface/s of vehicles rather they are designed as other formats (e.g. specific light systems or solutions).